Going to check the size of mine *hang on*
EDIT: Around the 250mb - 300mb mark by the looks
@funkylogik wrote:how much memory will that use m8 roughly? the backup?
Depends on what loaded on your phone , I'd say around 120 meg . ( SD Card ? )
Sorry thats what the custom ROM took
the phone backup was 280 meg .
As I said, I have no experience in creating device backups prior to installing a new rom but there seems to be a bit about it here - http://android.modaco.com/content/zte-blade-blade-modaco-com/329073/30-jan-guide-how-to-install-a-cu.... If you scroll down to '2. How to Install a ROM using Clockwork via Recovery Manager' there's a bit about making a backup in red text. I suspect it'll probably take up about 100mb on your sd card.